Motion Blur with Pflow problems

[ben_hamburg]

Hey,

I usually don?t render motion blur with vray, but rather add it in post, but for some heavy particle scene with fast moving small particles the post motion blur didn?t perform so well, so I tried the Vray motion blur.
But unfortunately I couldn?t render the scene, because I kept getting unhandled exception errors.

I?m guessing I have to many particles in my scene, but there is no way to reduce the amount...I ahve around 300k particles, although I tried to limit them somewhat with a camera culling operator.

Or is there anything else that could be the problem here? The particle flow is cached to disk with per frame precision, is that maybe the problem?

[Morbid Angel]

Do you have the particles dying in any way? if they are being killed of culled, then it could cause a problem since vray won't know frame to frame where the particle went. Instead you should scale them to 0. Its not ideal but I think it should work.

[ben_hamburg]

Hm...yeah, that could be what is happening. But the reason I?ve used the camera culling operator is to limit the particles, cause I?m worried I?ll run out of memory otherwise, and if i just scale them down they?d still be present, but I?ll give it a try to see if thats the cause.
If you have a better idea how to make a dense particle dust system over a long camera path...do let me know... I?ve been on that for a long time now and still haven?t figured out the best way to deal with that yet. Several particle systems and rendering them separately for the part the camera travels through them or something like that...
Although in my last test the After effects pixel motion blur did an ok job, so I?ll probably just go with that.

[Morbid Angel]

yeah sorry we moved to houdini from max long time ago so I cant help there

[yavor.rubenov]

Hello,

If you are getting unhandled exception errors - it would be best if you could send the scene to our support together with some info - what is your Max and V-Ray version.
300k are not that much and should render with no problem with motion blur.

Best regards,
Yavor

[ben_hamburg]

I will try to do that. Quite often while stripping down a scene for support the process itself makes clear what the problem is anyways...

[stevesideas]

Could you let me know what the result of this is. I had the same problem a little while ago when using motion blur and particles.

[ben_hamburg]

I think I have pinned down the problem and the solution: I?ve merged the particle flow in a new scene and then started working my way back to the original setup. It worked right up until I cloned the Pflow. The copy gave me the same unhandled error as the first.
Seems like I could fix it by simply creating a new Standard pflow, connecting the newly created PF_Source including the render op with the copied Pflow and deleting the PF_Source of the copied Pflow.
Renders fine now.

So I?m guessing it only occurs if you copy a Pflow or merge it in the scene with an existing Pflow or something like that.

[stevesideas]

Thanks for the update. I'm having the same problem yet again. I'll try what you said